1. Field of the Invention
The present invention relates to a hydrogen generation electrode used for an artificial photosynthesis module that decomposes an electrolytic aqueous solution into hydrogen and oxygen by light, and an artificial photosynthesis module including this hydrogen generation electrode.
2. Description of the Related Art
In the related art, as one of the forms in which solar light energy that is renewable energy is utilized, devices that use a photoelectric conversion material used for solar batteries and decompose an electrolytic aqueous solution to produce oxygen and hydrogen utilizing an electromotive force obtained with this photoelectric conversion material are suggested (for example, refer to JP-2012-1420A).
JP-2012-1420A describes a solar battery integral gas producing apparatus including a photoelectric conversion part having a light-receiving surface and its back surface, a first electrode for electrolysis that is provided on a back surface side of the photoelectric conversion part and was provided so as to be immersible in an electrolytic aqueous solution, and a second electrode for electrolysis that is provided on the back surface side of the photoelectric conversion part and is provided so as to be immersible in the electrolytic aqueous solution, and a switching part. The first electrode for electrolysis and the second electrode for electrolysis are provided so that the electrolytic solution can be electrolyzed by an electromotive force caused by the photoelectric conversion part receiving light to generate a first gas and a second gas, respectively. The switching part performs switching between a circuit that outputs the electromotive force caused by the photoelectric conversion part receiving light to a first external circuit, and a circuit that outputs the electromotive force caused by the photoelectric conversion part receiving light to the first electrode for electrolysis and the second electrode for electrolysis. One of the first electrode for electrolysis and the second electrode for electrolysis is a hydrogen generating unit that generates hydrogen from the electrolytic aqueous solution, and the other is an oxygen generating unit that generates oxygen from the electrolytic aqueous solution. Forming a pn junction using copper indium gallium (di) selenide (CIGS) or the like as the photoelectric conversion part is mentioned in JP-2012-1420A.